A combined chemical and enzymatic strategy for the construction of carbohydrate-containing antigen core units

Beta1,3-coupled disaccharides comprising the type I and type IV core disaccharide of carbohydrate-containing antigens are obtained by the glycosidase-mediated coupling of glycal acceptors with galactose. The beta1, 3-coupled disaccharide serves as an intermediary in chemical and enzymatic manipulation. An enzyme, beta1,6-N-acetylglucosaminyltransferase, facilitates the modification of the type IV disaccharide to a mucin-type trisaccharide, by a transfer of N-acetylglucosamine, to the 6-hydroxy position of N-acetylgalactosamine or galactose-reducing terminus.